It is generally known to form a catch selvage along the edge of a web being woven on a loom, for example using a rotating leno device to bind in the weft thread ends along the edges of the web using leno threads, so as to hold together the thread ends and hold the weft threads under proper tension. Once the weaving process has been completed, the catch selvage is trimmed from the edges of the woven web to form the finished cloth. The catch selvage material has therefore typically become waste.
If the weft thread material is of a different type than the catch selvage warp threads such as leno threads, then the trimmed catch selvage will include a mixture of different materials, which makes it difficult or impossible to reuse or recycle the catch selvage waste material. It is often the case that the leno threads comprise a different material than the weft threads, especially when the weft material is a high-cost, high-value material and/or a sensitive material with a low tensile strength that is subject to breaking. In these situations, the catch selvage warp threads, and particularly the leno threads, will be made of a stronger and/or lower cost material. The prior art has not provided any satisfactory and effective methods or apparatus for processing the trimmed catch selvage in such a manner so as to produce a type-pure weft thread waste separated from the leno threads.
European Patent Application 0,127,719, published on Dec. 12, 1984 discloses an apparatus for pulling or drawing off an auxiliary selvage, which is designated as a fabric list selvage or as catch selvage as the case may be, and which has been trimmed from the edge of a woven web produced on a loom. The apparatus is arranged near the web draw-off roller of the loom and comprises an auxiliary selvage drawing-off channel equipped with an injector nozzle. The auxiliary selvage, which comprises selvage warp and weft threads bound together, is trimmed from the edge of the web and is then pneumatically drawn off and conveyed into a waste container by means of the apparatus, without providing any measures to sort or separate the weft threads from the warp threads for the purpose of obtaining a type-pure waste directly at the loom.
European Patent Application 0,681,044, published on Nov. 8, 1995, discloses a method and an associated apparatus for drawing off the waste edges or the selvages of a woven web. The waste selvages formed along the edges of a web being woven on a loom are trimmed from the web and are then pulled between two driven drawing-off rollers that form a pulling nip for the waste selvage therebetween. The waste selvage is drawn through the rollers into a waste container. Thus, according to this reference, the waste selvage consisting of weft and warp materials bound together is drawn off and conveyed into a waste container by mechanical means, without carrying out any process for separating the materials in order to provide a type-pure weft material waste and a type-pure warp material waste directly at the loom.
German Utility Model 29,708,758 published on Sep. 11, 1997 discloses a loom including so-called rotational leno selvage forming devices for forming the fabric list edges and the catch selvages of a woven web being produced on the loom. According this reference, the rotational leno device twists or rotationally binds together two leno threads respectively to form the catch selvage and the fabric list edge. Thereby, the catch selvage which will become the waste selvage comprises only two leno threads binding together the weft thread ends. However, this reference does not disclose anything about the further processing or reuse of the catch selvage after it has been trimmed from the edge of the woven web.
Even using such a rotational leno device for forming the catch selvage, whereby it is possible to substantially reduce the number of catch selvage warp threads, it is still not possible to produce a type-pure waste in all situations, namely in situations using a different material for the leno threads relative to the weft threads as discussed above. Particularly in the case of weft yarns having a low tensile strength, such as a cashmere yarn or the like, such a cashmere yarn will not be used for the leno threads because this yarn is too weak in tensile strength and would lead to frequent leno thread breaks requiring stopping of the loom. In order to avoid such problems, up to the present day it has been typical to use a twisted wool thread as the leno thread. Such a twisted wool thread has a sufficient strength and quality to meet and exceed the requirements for use in a rotating leno device. However, such a wool thread will form a waste selvage that is not type-pure whenever the weft threads comprise a material other than twisted wool. The resultant mixed-type waste is less valuable and is not directly suitable for recycling or reuse in a spinning mill.
Furthermore, it has conventionally been necessary to supply the leno threads for a leno-bound catch selvage from respective leno thread spools. Additional processing steps and costs are involved in winding the leno threads onto the spools, storing the spools, handling the spools, mounting the spools on the loom for a particular weaving run, exchanging spools once they have been emptied, etc. The prior art has shown no suggestions toward totally avoiding the use of leno thread spools for supplying the leno threads.